Point Stephens NT General Area

Spaceport Darwin Proposal

Point Stephens NT General AreaSpaceport Darwin – 55Km Drive from Town.

by Robert Brand. It is clear that Australia needs a Space Agency and the Agency needs to help establish an Australian Spaceport. Given that it is only a matter of time I am very interested in Spaceport Darwin!

What is a Spaceport?

The Oxford dictionary simple states: a base from which spacecraft are launched.

These days, with spacecraft returning to earth for reuse and also for winged spacecraft, the definition must also include landing so a modern definition would be:  a base from which spacecraft are launched and landed.

Port Stephens in the Northern Territory of Australia, would seem to make an ideal spaceport. I believe that the land is mainly Crown Land on a perpetual lease to the Northern Territory Land Corporation. There are no buildings on the point and the land appears to be available for development. A gravel road is the only way of getting close to the site and it may currently be unpassable during the wet season.  The wet season tends to cause major access problems without high dry road access. Luckily the road traverses only high land, but the rain can make this road impossible to travel. If development starts, the road would need to be sealed from Darwin and also new roadways within the complex.

For those wanting to take a better look, it is on Google Earth and it is the land to the south east of Gunn Point NT Australia:

-12.180 Latitude and 131.160 longitude.

The land is 19km north to south and up to 11km east to west at the furthermost points.

Possible Australian Launch pointsWhy Spaceport Darwin?

In the picture to the right, I have outlined (in red) some areas suitable to launch. It would be ideally suited to an equatorial orbit and possibly a polar orbit. It should also be suited to a sounding rocket launch with a forward landing spot. There are few places that a space port should and can be built. There have been several false starts with Great Barrier Reef concerns and major land rights groups forming a huge lobby in Cape York. Inland sites tend to have severe restrictions on large launches because of the risks of launching over land and an population.

Australia does have Woomera, but it is inland and has massive issues for launching anything other than sounding rockets (straight up and down). Launching over water offers a way lower risk and the cost of insurance. Woomera’s costs are very high at the moment. Commercial launch sites are more competitive. The nearest large town is a day’s travel.

Any launch site needs to be capable of growing with the needs of the site and I expect that this proposed site should be able to grow to 4 launch pads for the future. Obviously it will start small, and grow with the need for local space services.

What Makes a Good Spaceport?

What are the important requirements of a Spaceport. This is not a spaceport for space tourism, but it could easily be included. We are looking at a serious launch facility in this proposal. The possibility exists to launch multistage rockets from this site. So as a launch facility, what essentials or important items do we need?:

  • In a country with financial stability.
  • In a country with political stability.
  • In a country with geological stability.
  • In a country with a well educated workforce.
  • Clear path to the east (equatorial orbit).
  • Clear Path to the north or South (polar orbit).
  • A safe distance from any public building or public road (8Km from launch pad).
  • Fresh Water. Lots of it.
  • Short distance to a major town.
  • Road, train, air and port facilities near by.
  • Ability to isolate the area for launches.
  • Construction work force.
  • Operational work force.
  • In town fabrication.
  • Land ahead capability for sounding rocket flights.
  • Close to the equator for equatorial flights.
  • Expansion for future launch pads
  • Private launch facilities / launch pads
  • 5km or longer runway a possibility.
  • Substantial power services.
  • Calm water in the launch area
  • A substantial distance from any airport
  • A substantial distance from town for safety reasons.

There are way more requirements or “should haves” like fuel handling facilities, but the ones above are a great start. Let’s see how Spaceport Darwin shapes up.

Essentially we have a green light on all of the above points. The only issue is the need for road works once the site becomes operational.

There are issues with the northerly launch, with a tight flight path between some islands. There is land only to the south.

Another benefit is the local waters to the east are only about 10m to 15m deep. This is well within normal scuba diving capability (usually 27m depth max for sports diving). Recovery of rocket components that may parachute to the water can easily be recovered.

A large observation area for the general public can be placed on the southern end of the complex Launch days attract many people that want to get close to the launch of a major space vehicle – even a small launch. It is essential to keep people 5Km from any launch. The launch pad should be 8Km away from public property. All of this is a green light for Spaceport Darwin.

There is a small national park to the east only a 10km kilometres away. It is small and only 8km wide. Human access is only by boat. Another small piece of land is crossed by any spacecraft launched to orbit and it is 170Km to the east. Most rockets will be in space or near to space by that time and the land is sparsely populated. This is perfect for a sounding rocket flight with a winged glider returning from space. There is even a sealed runway at Oenpelli Airport. This is 200Km distance from the launch site at 95 degree bearing and within gliding distance for a landing. The rocket would land in Van Diemen Gulf.

Electric power is not far away and fresh water is readily available from underground sources and large tanks can be filled over time before any launch. Water recovery following a launch is also possible.

There is plenty more to look at and assess, but Spaceport Darwin has a lot of positives and with operations cost being 60% or more for a launch, having local staff living in Darwin with a short drive each day is very attractive. Below is the Van Diemens Gulf map. Note most flights are likely to be in space or close to space as they pass over the land to the east. The population density is extremely low.

Space Port Darwin - Van Diemen Gulf NT

Spaceport Darwin Benefits

Spaceport Darwin will:

  • Attract high tech staff to the area
  • Increase local tourism
  • Improve unemployment figures
  • Create innovation in the region
  • Attract foreign companies and investment
  • Improve roads and services
  • Focus attention on the region as a global Space Hub
  • Have a 5km runway in the region for emergencies once fully operational.
  • Be a space tourism launch and landing site.

This discussion will continue over time. Please leave your comments about this site.

 – and yes, there are crocodiles!

Greetings Fellow Rocketeers

Did I say that we were Building a RocketDream Chaser spacecraft Graphic on top of a Rocket for Launch?

by Robert Brand. No we haven’t, but here is the buzz – we are developing significant rocket technology.

It was ThunderStruck team member David Galea that headed his email with “Greetings Fellow Rocketeers” and it may stick because ThunderStruck is building rocket technology. We may be building more rockets later but right now we are specifically building a booster for a bigger rocket. A booster that could make it to space all by itself with a ThunderStruck suborbital winged craft as the payload (mounted right on top of the thruster). The rocket will be configured as a sounding rocket – not orbital. The picture (above right) is a similar craft, but a way bigger craft, on top of a bigger rocket. Non the less it will look similar.

This will take years to build and it may result in a static test fire in the Australian desert in the next year or two depending on financing. None the less, it will be an amazing opportunity for a small company to gain considerable traction in the rocket building field.

The info here is a basic format that hopefully high school students can understand

Rocket design commencesRockets and Maths

Mathematics is essential in building space equipment, space craft and navigating in space to mention a tiny bit. Without maths, rockets would explode from over-pressure or fail to get to space because we over-engineered it and it was too heavy to be a work horse.

The image at right is a basic configuration. Solid fuel with an air core and a thrust and nozzle at the bottom. Looks simple, but the maths have to be done first to get an estimation of the pressure we can expect and the strength of the tank and the weight of the tank with different metals. note that as the fuel burns down from the inside towards the metal of the tank, the area burning is greater and the pressure thus increases in a big way. You can change the fuel configuration to burn slower or have less thrust, but that could change simplicity of equation below so we will assume that the fuel is the same for the entire burn. That has been done and we came up with two limits on the mass that we can now work with. The optimum design will be in the middle somewhere.

After putting a rough design on the table with a mass of 2,000Kg fully fueled, we managed to get to space with a big payload and a coasting altitude of 150Km or more. This was with a speed of 1.5Km (or more) per second at the 30 second burn when the fuel is exhausted.

A second design with 3,000Kg mass fully fueled only managed a bit less than 25km altitude. The optimum booster, configured as a sounding rocket lies somewhere in between. The next part of the work is to consider the options. That is:

  • Do we use more thrust and increase the tank and nozzle pressure?
  • We we increase the fuel load and mass?
  • Do we reduce the fuel load and mass?
  • Do we change the fuel and increase the pressure and  even the burn time?
  • Do we reduce the mass of the payload (250Kg in this initial desktop design?
  • Do we reduce the mass of the rocket?

These are just a few of the options, but how do we calculate these things – Mathematics of course.

Below are the maths for the heavier second design that only got to under 25Km configures as a rocket. It would have made a poor booster.

NOTE: this is a simple bit of maths for model rockets, but it applies to the bigger ones too. It is not the whole deal, but will give a good estimate for the first pass.

David Galea’s maths for the second configuration performance:

ThunderStruck Rocket Flight Profile – Estimated Calculations

There are three basic equations to find the peak altitude for the rocket

  • Max velocity v, the velocity at burnout = q*[1-exp(-x*t)] / [1+exp(-x*t)] = 916
  • Altitude reached at the end of boost = [-M / (2*k)]*ln([T – M*g – k*v^2] / [T – M*g]) = 13,191.684 m
  • Additional height achieved during coast = [+M / (2*k)]*ln([M*g + k*v^2] / [M*g]) = 11,515.9877 m

Total Height Achieved = 24,707.67 Km

All the terms in these equations are explained below on the method for using the equations.

  1. Compute Some Useful Terms
    • Find the mass M of your rocket in kilograms (kg):  2950kg
    • Find the area A of your rocket cross-section in square meters (m^2):  0.342m^2
    • Note that the wind resistance force = 0.5 * rho*Cd*A * v^2, where
      rho is density of air = 1.2 kg/m^3
      Cd is the drag coefficient of your rocket which is around 0.75 for a model rocket shape.
      v is the velocity of the rocket. You don’t calculate this drag force, though, since you don’t know what “v” is yet. What you do need is to lump the wind resistance factors into one coefficient k:
      k = 0.5*rho*Cd*A = 0.5*1.2*0.75*A = 0.1539
    • Find the impulse I and thrust T of the engine for your rocket. I= 3907501 Ns , T= 118841.27 Ns
    • Compute the burn time t for the engine by dividing impulse I by thrust T:
      t = I / T = 3907501 / 118841.27 = 32.88 seconds
    • Note also – the gravitational force is equal to M*g, or the mass of the rocket times the acceleration of gravity (g). The value of g is a constant, equal to 9.8 meters/sec/sec. This force is the same as the weight of the rocket in newtons.
  2. Compute a couple of terms, I call them “q” and “x”
    • q = sqrt([T – M*g] / k) = sqrt([118841.27  – 2950 * 9.8] / 0.1539) = 764.427
    • x = 2*k*q / M = 2 * 0.1539 * 764.427 / 2950 = 0.079759536
  3. Calculate velocity at burnout (max velocity, v), boost phase distance yb, and coast phase distance yc (you will sum these last two for total altitude).
    • v = 764.427*[1-exp(-0.079759536*32.88)] / [1+exp(-0.079759536*32.88)] = 660.916
    • yb = [-2950  / (2*0.1539)]*ln([118841.27  – 2950 *9.8 – 0.1539*660.916^2] / [118841.27  – 2950 *9.8]) = 13191.684
    • yc = [+2950  / (2*0.1539)]*ln([2950 *9.8 + 0.1539*660.916^2] / [2950 *9.8]) = 11515.9877

Rocket SoftwareDavid says: I have double checked my calculations with wolfram alpha (https://www.wolframalpha.com) with the same results.

Well fellow Rocketeers, we will continue to let you know about our big adventure with things that could “go BANG” as we develop our technology.

The Screen shot at right is a basic program that you can get for free or you can buy a more professional  version for model rocket hobbyists. None the less it is fine for early desktop modeling.

We will keep you in touch with the professional software that we will eventually choose and use for the serious design phase.

All you students, please get your head down and study maths. We will need to have capable people working in the space sector as Project ThunderStruck becomes an Australian Space staple.